1. Field of the Invention
The present invention relates to an optical information recording medium having a reversible display function, manufacturing method thereof and an image processing method using the optical information recording medium.
2. Description of the Related Art
Beisdes a read-only optical information recording medium, such as a DVD (Digital Versatile Disk), a recordable DVD (e.g., DVD+RW, DVD+R, DVD-R, DVD-RW and DVD-RAM) is put to practical use. These recordable DVD media, such as DVD+R and DVD+RW media are developed on an extended line of developing the technique for a conventional recordable compact disk, such as a compact disk recordable (CD-R) and a compact disk rewritable (CD-RW) and for maintaining the compatibility of the above-noted recordable DVD media with a read-only DVD, the recordable DVD media are designed in such a manner that the recording density (the track pitch and signal mark length) and substrate thickness of the recordable DVD media satisfy not only the requirements for CD but also the requirements for DVD.
For example, a DVD+R is produced, like a CD-R in such a manner that a substrate for the information recording in which an optical recording layer is disposed on a substrate by a spinning coating and on the optical recording layer, a metal reflective layer is disposed, is laminated through a laminating material with a substrate having the same form as that of the above-noted substrate for the information recording. In this case, for producing the optical recording layer, a dye material is used.
One of features of the CD-R is having a high reflectance (65%) which satisfies the requirements for CD. For obtaining a high reflectance by the above-noted composition of CD-R (or DVD+R), it is necessary that the light absorbing layer satisfies a specific complex reflectance at a wavelength of a recording/reproducing light.
A compact disk-read only memory (CD-ROM) or a digital versatile disk-read only memory (DVD-ROM) already has data recorded in them, at the time they have been produced and is used as a read-only optical information recording medium. In them, an index showing the recorded content or various designs is printed on the surface of the protective layer using an ultraviolet-curing ink or an oil ink. Such a printing is usually performed by a printing means, such as a screen printing or an offset printing. These printing means are suitable for a so-called mass printing in which the same pattern is printed in a large amount simultaneously.
When in a write-once optical information recording medium, such as a DVD+R, DVD-R and CD-R, an elecrtronic information or the like is recorded, the recorded data cannot be recognized unless the optical information recording medium is reproduced. Therefore, as a recording method of the above-noted index and various designs, the following methods are proposed. (1) a method for writing the index or designs on the protective layer using an oil felt pen, (2) a method for applying a thin label thereon for forming the indication, (3) a method for recording the indication according to an inkjet recording process by disposing an ink-receiving layer on the surface of the optical information recording medium (see Japanese Patent Application Laid-Open (JP-A) No. 05-238005) and (4) a method for recording the indication according to a sublimation dye transfer recording method by disposing a dye-receiving layer on the surface of the optical information recording medium ( see JP-A No. 08-48080)
On the other hand, a rewritable optical information recording medium, such as a DVD+RW, DVD-RW, DVD-RAM and CD-RW is disadvantageous in that in the case where the index or the like is recorded for the indication according to the above-noted felt pen recording method, inkjet recording method or sublimation dye transfer recording method, even if a recorded content is changed, the indication cannot be changed and an actual recorded content differs from the indication, so that the recorded content cannot be known by reading the indication. In this case, when by using a thin label used for the CD-R, the thin label is replaced with a new one repeatedly depending on the change of the recorded content for changing the indication, the optical information recording medium might be scratched.
After the optical information recording medium is inserted into a reproducing apparatus, the recording medium is clamped and while the recording medium is rotated, to the recorded-data read-out side of the recording medium, a laser light is irradiated through a pickup, thereby reproducing the recorded data. For performing the insert of the optical information recording medium into the reproducing apparatus or the reproduction of the recorded data stably and reliably, the specifications for the thickness, the warpage and the dynamic in balance of the optical information recording medium are prescribed. When a printing medium is adhesive-bonded to the printing indicating surface of the label surface of the optical information recording medium without consideration of the above-noted propertries of the optical information recording medium, the mass balance (the so-called dynamic in balance) of the produced optical information recording medium is impaired. When the dynamic in balance is impaired, the optical medium is rotated irregularly and the reproducing and recording of the information may have a defect. Recently, for enhancing the transfer rate of the data, a large rotation number is required and it is necessary that the dynamic in balance is more improved, so that in the printing of the title, the optical information recording medium has preferably a thickness which is near to the above-noted specification.
In the case where the title or the like is printed on the printing indicating surface of the optical information recording medium using a printing apparatus, when the heat applied by the thermal head to the data recording layer, is transmitted excessively to the data recording layer, the recorded data become destroyed. Due to the variety of the warpage and thickness which the optical information recording medium usually have, the adhesion properties of the printing medium with the thermal head are impaired and when the heat from the thermal head is not uniformly tranmitted to the color-developing layer of the recording medium, the printing quality is lowered. Therefore, JP-A No. 08-180642 proposes the strengthening of the adhesion properties of the printing medium with the thermal head by disposing a flexible resin layer as an under layer of a layer in which the ink for the thermofusible transfer printer can be fixed. JP-A No. 2000-155989 proposes a technique of preventing the heat transmitting to an optical recording member by disposing a thermal insulating layer between the optical recording member and a thermosensitive color developing layer. However, in the above-noted two disposals, when the flexible resin layer or the thermal insulating layer is individually disposed, a disadvantage is caused respectively wherein the transmission of the heat to the optical recording member can be difficultly prevented or wherein the adhesion properties of the printing medium with the thermal head cannot be satisfactorily improved.
In the case where a printing medium is adhesive-bonded on the printing indicating surface of the label surface of the optical information recording medium, depending on the wrapage degree of the optical information recording medium, the adhesion properties of the printing medium with the thermal head are impaired and with respect to the indication of the printing medium, a defect is caused. The adhesion between the printing medium and the thermal head varies depending on the size of the thermal head as follows.
When an optical information recording medium having a warpage angle of within ±0.7° is contacted with a printing indicating medium using a thermal head having a size of 35 mm, the maximum distance between the optical information recording medium and the thermal head is so large as 30 μm to 60 μm, so that the adhesion between the printing medium and the thermal head is impaired and a disadvantage is caused wherein the image display of the printing medium becomes ununiformly.
Accordingly, an optical information recording medium by which the getting thereof in and out of a reproducing apparatus and the reproducing of recoding data can be stably and reliably performed and the recording content can be visually confirmed, and which has the reversible display function of performing at least one of the recording, erasing and rewriting of the display which is excellent in the uniformity of the image, easily, with a good appearance and without damaging the optical information recording medium, has not yet been provided and a prompt development thereof has been desired nowadays.